Le polygraphe: Lucie Champagne is given the role of the victim, Marie-Claire, in a film of a true, unsolved murder. By coincidence, Lucie's neighbour Francois, was Marie-Claire's boyfriend. He is a suspect in the continuing investigation and is unsure of his own innocence although he has an alibi from his previous girlfriend, Claude. Francois' polygraph (lie detector) test proves inconclusive and while he awaits his second test, Lucie's film is completed with its own ideas on who killed Marie-Claire.